Increasing prevalence of extreme summer temperatures in the U.S.
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Human-caused climate change can affect weather and climate extremes, as well as mean climate properties. Analysis of observations and climate model results shows that previously rare (5th percentile) summertime average temperatures are presently occurring with greatly increased frequency in some regions of the 48 contiguous United States. Broad agreement between observations and a mean of results based upon 16 global climate models suggests that this result is more consistent with the consequences of increasing greenhouse gas concentrations than with the effects of natural climate variability. This conclusion is further supported by a statistical analysis based on resampling of observations and model output. The same climate models project that the prevalence of previously extreme summer temperatures will continue to increase, occurring in well over 50% of summers by mid-century.
KeywordsBias Correction Global Climate Model Natural Climate Variability Extreme Summer Temperature Gridded Observational Dataset
Claudia Tebaldi acknowledges support from the US Department of Energy, Office of Biological and Environmental Research, grant DE-SC0004956 and thanks the Climate and Global Dynamics division of the National Center for Atmospheric Research, Climate Change Research section, for hosting her.
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